The present invention is directed to an improved scratch-and-sniff coating particularly for use in the food and beverage industry.
There are normally two approaches to providing a scratch-and-sniff coating. The most common approach is to encapsulate a flavor in microcapsules, and subsequently coat the microcapsules onto a substrate. However, this well known technique has two major disadvantages, particularly in the food and beverage industry. First, the technique is limited by the chemical composition of the flavor formulation. Since most flavor systems contain multiple chemical components, chemical and physical reactions such as polymerization, coacervation, etc. which may be necessary in the microencapsulation process may be adversely affected. Second, the technique is limited by the materials used to form the capsule walls. Wall materials such as aminoplast resins, or polyurethane, are prepared from toxic chemicals, such as formaldehyde and isocyanate, whose use in the food and beverage industry is discouraged.
A second approach is to disperse oil droplets in a polymer solution, and when the aqueous dispersion is allowed to dry to form a coating on the substrate, the oil droplets are entrapped in the dried polymer film. However, to achieve such a dispersion system, oil thickeners or bi-liquid foams are preferred. Since the coating matrix comprise water soluble polymers, the coating is not water resistant, which is required in the food and beverage industry. Such a technique is described in U.S. Pat. Nos. 5,290,547 and 6,312,760.
Scratch-and-sniff coatings are described, for example, in U.S. Pat. Nos. 3,655,129; 4,243,224; 4,254,179; 4,687,203; 4,898,633; 5,114,735; and 6,102,224, as well as WO 96/37098.
The use of fragrance or flavor delivery means on packages or beverage containers is known as shown by U.S. Pat. Nos. 4,717,017; 4,720,423; 5,249,676; 5,635,229; and 6,102,224.